Subcutaneous adipose tissue blood flow and triacylglycerol-mobilization during prolonged exercise in dogs

In 6 dogs concentration differences for glycerol and FFA were measured between the aorta and the external pudendal vein, a vein which mainly drains subcutaneous adipose tissue in dogs, during prolonged exercise. It was found that the a-v differences increased about 2-fold for both glycerol and FFA, however great interindividual differences were found. In 4 dogs adipose tissue blood flow, glycerol and FFA a-v differences were measured simultaneously, and the mobilizations of glycerol and FFA as well as the re-esterification of FFA were calculated. After 2 h of exercise the values were in the range of 1-7 umol/(100 g.min) for FFA and glycerol mobilizations while the FFA re-esterification was in the range of 2-14 umol/(100 g.min). It was found that the FFA/albumin ratio in adipose venous blood, on average 3.6 was at a level at which the FFA mobilization has been shown to depend on the adipose tissue blood flow in isolated fat pads. In 11 dogs subcutaneous adipose tissue blood flow rose 2-fold during exercise from about 5-10 ml/(100 g.min). It is concluded that the subcutaneous adipose tissue blood flow response to exercise is equal in man and dog, that lipolysis, FFA mobilization and FFA re-esterification are increased in subcutaneous adipose tissue during exercise, and that the increase in blood flows is of importance for the enhanced FFA mobilization during exercise.